Electrical power plug



Dec. 1, 1959 M. MORSE ELECTRICAL POWER PLUG 2 Sheets-Sheet 1 Filed May3. 1957 infin/l fil: i l

Dec. 1, 1959 MMMM RSE 2,915,737

2,915,737 ELECTRICAL POWER PLUG Milton Morse,'Bronx, N.Y.

Application May '3, 1957, Serial No'. 656,938

4 Claims. (Cl. 339-1195)` This invention relates generally to electricalconnectors and more particularly to power plugs of the double bladedtype.

` Heretofore in connection with apparatus requiring a relatively heavypower supply, it has beencustomary to use connection plugs which werebulky, thus 'necessitating undue enlargement of the apparatus andparticularly chambers adapted to receive the coiled wire and plug.

' It is therefore among the principal objects of the present inventionto provide electrical connection plug construction of the bladed type,which is adapted to accommodate relatively large conductors and yetwhich is of unusually compact arrangement.

. Another object herein lies in the provision of electrical connectionplug construction, whichl although compact, is extremely durable so thatthe plug may be subjected to considerable abuse without damage.

'4 Astill further object of the presentinvention lies in the provisionof electrical connection plug construction in which the blade elementsare supported at a plurality of points to assure rigidity and constantalignment even under considerable stress.

A feature of the invention lies in the fact that the insulating mediumof which the body element is composed maybe of a rigid durable typeadapted to resist the effect of heat and moisture. This medium, isequally adapted to resist the effects of extremely low temperatures.Insulating materials of this character, however, are subject usually tothe objection of brittleness and low impact resistance to shock. Byvirtue of the coaction therewith of the shell element the body isreinforced and protected.

Another feature of the present invention lies in the provision of animproved formv of strain relief element which is strongly integratedwith the shell element and which is adapted to securely engage theconductor with which the plug is used so that stresses upon theconductor are not communicated to the points of connection of theconductor with the contact screws.

Another object herein lies in the provision of structure whereby thepermanent engagement of the blade element, with the body element, isquickly performed andpositively maintained.

One of the important requirements of plugs of the type described is thatthe blades maintain their position so that quick' and positiveconnection and disconnection may be made with a female type receptacleof standard predetermined dimensions. Since it is desirable to use arelatively brittle insulating medium for the body because of its weatherand temperature resisting characteristics, it is desi-rable that themetal parts have a relatively tight t therein.' This raises theobjection that when the parts are assembled, unless the tolerances arekept extremely fine, the brittle body will be shattered with aconsequent loss in production. In accordance with the present invention,the resiliency characteristics of the material of which the blades areformed is taken advantage of, whereby the prong members on thebladeelement are curved to obtain proper purchase on the walls of thechannel in which they toA choring lug receiving channels 33 to 36inclusive.

ice

are secured. This enables the channels in which they are.

secured lo be moulded oversize thereby reducing breakage whilemaintaining proper interblade spacing and alignment.

Another object herein lies in the provision of structure of the classdescribed wherein conductors of relatively large diameter may beaccommodated, the outer cover of the conductor being substantially equalin size to thev interblade spacing, and wherein the exposed blades aresupported close to their own axis.

Still another object herein lies in the provision of structure oftheclass described wherein the inner metallic parts thereof e.g. theconnecting blades are completely and permanently insulated from theouter metal shell, so as to avoid all possibility of the same becomingcharged at anyA time during the useful life of the same.

These objects and other incidental ends and advantages will more fullyappear in the progress of this disclosure and be pointed out in theappended claims.

In the drawings, similar reference characters designate correspondingparts throughout the several views.

Figure l is a perspective view of an electrical connection plug showinga first embodiment of the invention. n

Figure 2 is an exploded perspective view of the plug Figure 5 is a viewin perspective showing a pair of in' sulating plugs comprising a part ofa second embodiment of the invention.

Figure 6 is a longitudinal sectional view as seen from the plane 6-6 onFigure 5.

' Figure 7 is a fragmentary sectional view corresponding-"i to that seenon Figure 3 showing the second embodiment of the invention. f

Figure 8 is a fragmentary sectional view corresponding to that seen onFigure 4showing the second embodiment of the invention.

Figure 9 is a plan view of an insulating plug comprising a part of athird embodiment of the invention.

Figure l0 is a fragmentary sectional view cor-responding to that seen onFigure 4 but showing the third embodiment of the invention.

Figure 1l is a fragmentary sectional view correspond4 ing to that seenon Figure 3, but showing the third embodiment of the invention.

ln accordance with the first embodiment of the invention, the electricalconnection plug generally indicated by reference character 10 comprisesbroadly: a body element 12; a shell element 14; blade elements 16 and17; insulating plugs 18 and 19, and a strain relief element 20. The plug10 may also include an insulating wafer 22, when desired.

As best seen on Figures 2, 3, 4, and 6, the body element 12 ispreferably of generally oblong shape including front wall 24, rear wall25, and end walls 26 and 27, wall 28, and top wall 29, having a recess30. The body 12 is preferably composed of a suitable insulating materialhaving the requisite resistance to weather and temperature conditions.Suitable materials are synthetic resins of the phenolic, alkyd type, orpolystyrene or lthe like. In view of the support produced by the shellelement, relatively brittle materials may be used such as ceramics. Therecess 30 provides the upper surface 31 and extending downwardlytherefrom is the central cylindrical opening 32 through which theconductor may pass. Extending downwardly from said upper surface 31 area plurality of an- The channel 33 and 34 and the channel 35 and 36, attheir Patented Dec. 1, 1959y 3 lower 'ends communicate with pockets 37and 33 respectively. Disposed outwardly of the opening 32 are a pair ofscrew shank receiving sockets. It is to be noted that the channels 33 to36 inclusive are disposed between the open-l ing 32 (for the conductor)and the sockets 21 and 23.

The blade elements 16 and 17 are substantially identical so that adetailed description of one will suffice for both. In order to avoidunnecessary repetition certain of the parts on the blade element 17 aregiven the same reference characters as the blade element 16 with theaddition of the suffix a.

The blade element 16 is preferably formed from a planar piece ofconductive material having the desired physical properties, as forexample, preferably 1/2 to 3A hard brass .G64 inch thick. The bladeelement 16 includes a blade member d1, a base 42, upwardly directedcorners 43, a threaded opening de, and a pair of downwardly extendinganchoring lugs 47 and 48. The lugs 47 and 48 are generally parallel tothe plane of the prong member.

The anchoring lugs are curved as best seen in Figures 2 and 5. Whilethey are shown there as being curved in the direction of the base 42they may be curved in the opposite direction.

By virtue of the shape and arrangement of the plug body element 12,there is a web 45 disposed between the channel 33 and 34, and acorresponding web 46 disposed between the channel 35 and 36. Thethickness of these webs from front to rear is substantially equal to thedistance between the inwardly disposed surfaces of the anchoring lugs 47and 43. The length of the anchoring lugs 47 and 48 is each suliicientlygreater than the vertical height of the web against which it is disposedin the assembled plug to provide terminals 52 and 53 which are swagedabout the lower surface of the web d5.

As seen in Figures 3 and 4, binding screws 50 and 51 are engaged withthe bases 42 and 42a in a well-known manner for securing the terminalsof the conductor.

As best seen in Figure 4, terminals 52 and 53 of the anchoring lugs l)and 5l are swaged toward each other about the lower surface of the web15. This is preferably accomplished by pressing against a tool (notshown) having a. concave inner surface which curls the terminals towardeach other so that they securely grip the web, thus preventing theremoval of the blade element 16 from the plug body 12. The plug bodyitself serves as a guide to hold the anchoring lugs in such position asto properly receive the staking or swedging tool.

The shell element 14 is of generally cup shape having front and rearwalls 54 and 55, end walls 56 and 57, and a bottom wall 58. The bottomwall 58 is provided with a central opening 59 through which theconductor may pass, and a pair of oblong holes 59 and 6d. The shellelement 11i is maintained in place by crimping the upper edge 61, aboutthe upper edge of the plug body element t 12. (See Fig. 3.)

The insulating plugs 13 and 19 are generally similar, each being wedgeshaped and having a longitudinal trape- Zoidally configured crosssection. The plugs are bounded by an inner surface 70, an outer surface71, end surfaces 72 and converging surfaces 73 and 7d. The plugs areformed of any suitable non-conductive material which will match theelectrical insulated properties of the plug body, while being able toadapt itself to the coniiguration of the channels in which it isdisposed. Epoxy resins with a lightweight cellular filler have beenfound to be suitable, the same being employed as a putty like substancedirectly into the channels 33-36, or if desired, the plugs may be moldedfrom synthetic resinous material such as Bakelite, silicone, rubber orthe like. The plugs are imerted after the staking of the anchoring lugs5@ and and prior to the assembly of the plug body element 12 within theshell element 14. The presence of the plugs 1S and 19 prevents the entryof dirt or other conductive material which may become lodged within thechannels to prevent the possibility of charging the vshell element whenthe Adevice-s connected with an electrical outlet.

The strain relief element 20 includes a stationary member 62, and amovable member 63. The member 62 is of irregular configuration best seenin Figure 2, and it is of generally U-shape including a pair of tabswhich are adapted to be inserted in holes 59land 60 of the shell element14. The tabs.64 and 65are retained within the holes 59 and 60 bystaking. The movable member 63 is provided with a pair of threadedorifices with which the screws 66 are adapted to engage. This permitsthe complementarily arranged curvedportions of the members 62 and 63 togrip the conductor 11.

After the blade elements have been assembled upon the body element, thisassembly is partially encased by the shell element 14.

With the electrical connection plug 10 in a fully assembled condition,it may be seen that the blade members 41 and 41a are maintained in aproperly aligned spaced and parallel condition so that they may properlyengage with standard receptacles. This alignment is assured byA the factthat the bases 42 and 42a are perpendicular with respect to said blademembers. The bases are maintained in contact with the upper surface 31which is planar by the anchoring lugs 47 and 48 which are pulled downtight about the webs 45 (and 46).

in the normal manufacturing production of the blade elements 16 and 17,the curvature of the anchoring lugs, assures Contact with the channelsurfaces (see Fig. 3).

By virtue of the fact that the blade element is supported by twoanchoring lugs which are substantially in the plane of the blade member,a very large opening for the passage of the conductor may be used(substantially of a diameter equal to the distance lbetween the bladement-4 bers or larger). The blade elements are supported in the bodyelement at 'a point Where the platform adds additional support to theblade rather than being in such a position as to increase the leverageby which the blade member may act as a lever to pull the anchoring lugs,out of the body element.

Turning now to the second embodiment of the invention, as illustrated onFigures 5, 6, 7'and 8, parts corresponding to those of the rstembodiment have been desig.

nated by similar reference characters with the additional. prefix 1.

The second embodiment of the invention differs from the rst embodimentin the provision in each insulating plug 11S and 119 of a pair of curvedrecesses of generally cup-shaped configuration. The anchoring lugs and.

151 are formed to be slightly longer in total length than. thecorresponding lugs of the first embodiment, so that upon insertion ofthe plugs 118 and 119 a camming action.

results in the staking of the terminals 152 and 153, respectively. Byforming the plugs 118 and 119 of toughand resilient synthetic resin, aslight blow on the outer surface of the plug easily stakes the terminalsas indicated on. Figure 8. This eliminates the need for a separatestaking. operation before the insertion of the insulating plugs as isnecessary in the case of the first embodiment. In other respects, thesecond embodiment of the invention resem. bles the first embodiment.

Turning now to the third embodiment of the invention, partscorresponding to those of the first embodiment have been designated bysimilar reference characters with` the additional preX 2.

The third embodimenty of the invention consists in essence of futuremodification of the second embodiment, in which curved recesses St) and81 in the plugs 118 and 119 are provided with an overhanging portion 85against which the staking action completed. This construction resultsnot only in a self-staking operation as the plugs 213 and 219 areinserted, but in the employment of the stake portions to retain. theinsulating plugs in position within the plug body.

Even though the channels. 33-36 may be slightly oversized to allow forirregularity4 I wish it to be understood that I do not desire to belimited to the exact details of construction shown and described forobvious modification will occur to the person skilled in the art.

I claim:

1. An electrical connection plug comprising: a body element having apair of spaced channels, a blade element having a pair of anchoringlugs, said lugs being disposed one within each channel, said body havinga wedgeshaped pocket therein communicating with said channels, said lugsbeing staked within said pockets, and a Wedgeshaped insulating plugIdisposed within said pocket and sealing said channels.

2. An electrical power connection plug comprising; a body element havinga channel, a blade element having a blade member, a base and at leastone anchoring lug, said lug being substantially in the plane of saidblade member, said anchoring lug being disposed within said channel, andan insulating plug disposed Within and sealing said channel, saidinsulating plug having a curvilinear recess positioned to contact an endportion of said lug to stake the same against said channel.

3. Electrical power connection plug construction comprising: a bodyelement having a plurality of channels; a blade element having a blademember, a base, and a plurality of anchoring lugs; said lugs beingsubstantially in the plane of the blade member, and being disposed eachwithin one of said channels; and an insulating plug disposed Within andsealing said channels, said insulating plug having a plurality ofcurvilinear recesses therein positioned to contact an end portion ofeach of said anchoring lugs to stake the same against said channel.

4. Electrical power connection plug construction comprising: a bodyelement having a plurality of channels; a blade element having a blademember, a base, and a plurality of anchoring lugs thereon, said lugsbeing substantially in the plane of said blade member, and beingdisposed one Within each of said channels; and an insulati-ng plugdisposed Within and sealing said channels, said insulating plug havingat least one curvilinear recess therein bounded by an overhangingportion for each of said lugs, said recess being positioned to contact aportion of an anchoring lug to cam the same into contact with saidoverhanging portion whereby said insulating plug may be maintainedwithin a channel in said body element.

References Cited in the tile of this patent UNITED STATES PATENTS

